Road grading and tamping appliance

ABSTRACT

The road grading and tamping appliance (1) has a bottom plate (2) and at least one rotating, eccentrically-supported and driven weight for providing vibration. The bottom plate (2) is provided with a shaft (5) disposed perpendicular thereto and on which the rotating eccentric weight (10) is rotatably supported, specifically at a predetermined distance from the bottom plate (2). The eccentric weight (10) consequently rotates in a plane parallel to the bottom plate. By adjustment of the rotating eccentric weight (10) axially of the vertical shaft (5), the eccentric action, that is the leverage action, on the bottom plate (2) can be reduced or increased.

The invention relates to a road grading and tamping appliance with abottom plate and a revolving, driven and eccentrically-supportedcentrifugal weight.

Background various constructions of road grading and tamping appliancesand known in which an eccentrically-supported weight is kept inrotation. In road rollers with roller cylinders rotating about an axle,the eccentrically-supported weights rotate about the axle of the drums,that is about a horizontal axle. Other types of road grading and tampingappliances which are equipped with one bottom plate or a plurality ofbottom plates have vibratory device so designed that the eccentricweights are supported on a horizontal axle shaft. In both cases thecentrifugal force of the eccentric weights, or the conforming componentsof same, takes effect, with level ground surface subjected tocompaction, in the direction perpendicular to that surface. Thecentrifugal force of the eccentric weight is greatest when the eccentricweights are vertical in the lower or upper position. In each otherposition of the eccentric weights only components of the action of forcein the downwards or upwards verticals are operative. This means thatonly a small component of the eccentric rotating weights can be used forthe compaction of the ground.

THE INVENTION

It is an object to provide a road grading and tamping appliance in whichthe rotating eccentric weight can be fully used for the compaction ofthe ground.

In accordance with the invention the bottom plate has arrangedperpendicular thereto a shaft which is provided with an eccentric weightor a plurality of eccentric weights in a plane situated parallel to thebottom plate and at a distance from the latter.

In the case of such a road grading and tamping appliance, a which theeccentric weight or mass is arranged horizontally on a vertical shaft,the eccentric rotating weight is operative in a horizontal plane. Asthis so-supported eccentric weight is operative at a predetermineddistance from the bottom plate, a lever force is applied via thevertical shaft or axle of the road grading and tamping appliance. Thebottom plate is tipped, or tilted into a rocking position, continuouslyall around, and thereby performs a wobbling motion by tilting the bottomplate in a circular orbit as the mass rotates. The ground isconsolidated or compacted in this region through this wobbling motion ofthe bottom plate. The vertical shaft transmits the moment produced aboveto the bottom plate in like manner, so that a consolidation of theground is accomplished through the constant wobbling motion of thebottom plate. This consolidation or compaction takes place rapidly allround, that is the energy of the eccentric weight is constantlyconverted into ground compaction or compression work. With increasingcompaction of the ground the vibration or the wobble effect of the roadgrading and tamping appliance is reduced and this serves as anindication of compaction being completed. One eccentric weight only issufficient in the case of the road grading and tamping appliance inaccordance with the invention.

According to a further feature of the invention, the rotating eccentricweight can be adjusted in the axial direction of the vertical shaft. Inthat way the lever action or the moment is reduced or increased as afunction of the length of the lever arm, and this signifies a reductionor increase of the compaction work. Moreover the rotational speed of therotating weight may be modified. In particular the road grading andtamping appliance may be so formed that there is rigidly connected withthe bottom plate a casing in which is supported for rotation the shaftdisposed vertically to the bottom plate. The rotating eccentric weightis arranged displaceable along the shaft and can be adjusted the lockedby means of an operating device movable along a casing guideway, forexample a slot. There may be joined with eccentric weight asleeve-adjacent piece which supports a roller bearing. The operatingdevice may with this engage by means of a forked end piece or the likethe outer ring of the roller bearing.

The casing is preferably surrounded by a casing jacket, radially andaxially disposed resilient shock-absorbing members being arrangedbetween the casing and the casing jacket. The casing jacket ispreferably provided with a pole, which is interchangeably fittedthereon. to cause traveling of the road grading and tamping appliance.

The bottom plate preferably has a plane round bottom surface. A slightoutwardly-directed camber may also be provided for the bottom surface. Adriving device for the shaft may act on the upper end of the verticalshaft through the intermediary of a flexible coupling. This drivingdevice may be a motor of any kind, preferably an internal-combustionengine, an electric motor or the like. The driving device is preferablymounted on the casing jacket.

A plurality of road grading and tamping appliances may be coupled withone another, this being effected, for example, by resilient linkage ofthe casing jackets. With such a coupling care is to be taken that thespeeds of the waves of the road grading and tamping appliances and therotations of the eccentric weights are synchronized with one another,for example through the intermediary of appropriate gearing and thelike.

Embodiments of the invention are hereinafter described in more detailwith reference to the accompanying diagrammatic drawings, in which:

FIG. 1 is a sectional elevation of one embodiment of road grading andtamping appliance in accordance with the invention;

FIG. 2 is a cross-section along the line II--II in FIG. 1;

FIG. 3 is a cut-away portion of a cross-section along the line III--IIIin FIG. 1; and

FIG. 4 illustrates the coupling of two road grading and tampingappliances in accordance with the invention.

The road grading and tamping appliance 1 includes a bottom plate 2which--seen in plan (FIG. 2)--represents a circular disk. A casing 3 isfixedly connected with the bottom plate 2 by means of bolts 4. A shaft 5is rotatable within the casing 3 by means of the roller bearings 6 and7. The casing 3 is be closed off at its upper end by the cover plate 8.The cover plate 8 is fixedly connected with the casing 3 by the bolts 9.An eccentrically-supported weight 10 is joined on to the shaft 5 forrotation therewith by means of the part 11. The eccentrically-supportedweight 10 has a sleeve portion 10a (FIG. 3) a sleeve-like extension 12(FIG. 1) on which a roller bearing 13 is located. An operating element14, for example a bar, handwheel or the like, is guided through avertically-extending slot 15 in the wall of the casing 3 and grips witha forked end piece 16 about the outer ring 13a of the roller bearing 13.By moving the operating element 14 along the slot 15, the sleeve portion10a with the eccentric weight 10 can be displaced upwardly or downwardlyalong the shaft 5. The mass 10 is spaced always above the bottomplate--see FIG. 1--by at least its thickness, to provide a suitablelever arm to cause wobble of plate 2. The eccentric weight 10 can belocked at any desired higher level on the shaft 5 by screwing theoperating element 14 up on the threaded bolt 17 and tightening itagainst casing 3. The casing 3 and a plate 18 fronting same are likewiseprovided with suitable slots 19 and 20.

The casing 3 is surrounded by a casing jacket 22 between which and thecasing radially-extending shock-absorbing members 23 are arranged. Thecasing jacket 22 rests on vertically-arranged shock-absorbing members24. The casing jacket 22 is fitted with a handle, or pole 25 secured ina sleeve 26 fast with the wall of the casing jacket 22. The handle orpole 25 can be interchangeably inserted onto sleeve 26. The handle, orpole is clamped in the sleeve 26 by a clamping screw 27.

The upper end 5a (FIG. 2) of the shaft 5 is connected for rotationdriving shaft 29 of a driving motor 30 or the like by a flexiblecoupling 28 with a. The flexible coupling 28 consists of the bushings 31and 32 (FIG. 7) together with the resilient intermediary member 33 andthe tie bolts 34. The motor 30, for example an internal-combustionengine, an electric motor or the like, is joined through a flange 35with the flange 36 of the supporting casing 37 which is fixedlyconnected to the casing jacket 22 by means of the bolts 38. The casingjacket 22 can be turned on the supporting shock-absorbing members 24 bythe handle or pole 25, as required.

The bottom plate has a bottom surface 2a (FIG. 1) which is in the formof a plane round bearing surface. A bevel 2b may be provided at theperiphery. The bearing surfaces of the bottom plate may also be slightlycambered. The bottom plate may also have a different shape in plan; forexample square, quadrangular and polygonal.

OPERATION

The eccentric weight 10 revolving with the driven shaft 5 sets up acentrifugal force radially in a horizontal plane which, because of thespacing of the eccentric weight from the bottom plate 2--in whateverposition is considered--exerts a tilting moment. This moment is alsoeffective on the bottom plate, so that the bottom plate, at the verypoints at which the eccentric weight is located, is pressed more firmlyonto the ground than at the diametrically-opposite points. As theeccentric weight revolves constantly, this tilting moment takes effectall round in rapid sequence. There comes about at the bottom plate anall-round continuous vibration through which the ground is subjected toa compacting action. Travelling of the road grading and tampingappliance in the desired direction can be controlled by slightmanipulation of the pole or handle 25. The lever arm with which thecentrifugal force is operative on the bottom plate is varied byelevation adjustment of the eccentric weight 10 along the shaft 5. Thegreater the lever arm, the greater become the moments to be transferred,whereby the performance of the vibratory arrangement can be regulated.It is moreover, possible to modify the rotational speed of the drivingshaft, and therewith of the vibratory shaft, by appropriate control ofthe driving motor. The shock-absorbing members interposed between thecasing and the casing jacket suppress any vibration of the pole orhandle 25 so that the road grading and tamping appliance can be wellmanaged by hand. The bottom plate is interchangeably arranged on thecasing, so that bottom plates of different diameters can be used. Theroad grading and tamping appliance is structurally compact and is goodfor work of remarkably great compaction.

It is moreover, possible that two or more than two road grading andtamping appliances 1 can be coupled with one another. In so doing, forexample, the casing jackets 22 may be kept connected with one anotherthrough a rigid or flexible connecting link 40 (FIG. 4), the drivingshafts 29 being synchronizable with one another, for example by means oftoothed wheels 41 and serrated belts 42. When road grading and tampingappliances are coupled together, superposed vibrations will resultthrough which a compaction power for the ground is also achieved.

I claim:
 1. Soil compaction and tamping apparatus havinga bottom plate(2) having an essentially circular bottom surface (2a); a verticalsupport means (3, 22); means (4) for securing the vertical support meansto the bottom plate; motor means (30); and comprising, in accordancewith the invention means for applying a rocking or tilting movement tothe bottom plate in a circular orbit of the bottom surface (2a) withrespect to soil to be compacted comprising a rotatable shaft (5)extending in a vertical direction from at least approximately the centerof the bottom plate, and drivingly coupled to the motor means; and aneccentric weight or mass (10) secured to the rotatable shaft to revolvetherewith, at a predetermined height above the bottom plate (2) togenerate, upon rotation of the shaft, a force moment acting on thebottom surface of the bottom plate by the lever arm formed by thedistance of the weight, or mass above said bottom surface plate andthereby effect said tilting of the bottom plate and wobbling and tiltingmotion thereof.
 2. Apparatus according to claim 1 wherein the revolvingeccentric weight or mass (10) is height adjustable in axial direction onthe vertical shaft (5).
 3. Apparatus according to claim 1 wherein thesupport means comprisesa hollow casing (3); the shaft (5) beingjournalled within the casing; and adjustable means (14, 16) engaging thecasing and coupled to the weight or mass for securing said weight ormass in predetermined, height adjustable position above the bottom plateto thereby permit adjustment of the length of the lever arm and adjustthe force moment of tilt, upon rotation of the eccentric weight or massbeing transferred to said bottom plate.
 4. Apparatus according to claim3 wherein said adjustment means comprises a clamp (14) engaging saidcasing (3) to determine the vertical position of the eccentric weight ormass.
 5. Apparatus according to claim 3 wherein said height adjustableeccentric weight or mass (10, 10a) includes an extending sleeve (12)vertically extending along the shaft (5);the adjustable means includes afork element (16) surrounding said sleeve; and bearing means (13)interposed between said fork and said sleeve.
 6. Apparatus according toclaim 1 wherein the support means includes a hollow casing (3), theshaft (5) being journalled within the casing;a jacket (22) surroundingthe casing; and resilient shock absorbing members (23, 24) positionedradially (23) and axially (24) between the casing (3) and the casingjacket.
 7. Apparatus according to claim 6 further including a handle orpole (25);and means (26, 27) for releasebly and interchangeablyattaching said handle or pole (25) to the casing jacket (22) to permitoperator control of said apparatus.
 8. Apparatus according to claim 1wherein said motor means (30) is positioned at the upper end of saidvertical shaft.
 9. Apparatus according to claim 6 wherein said motormeans is secured to said casing jacket (22) at the upper end of saidshaft (25);and a flexible coupling (28) is provided, interposed betweensaid motor means and the shaft.
 10. Apparatus according to claim 9further including a support flange (36) secured to the casing (22)adjacent the upper end (5a) of the shaft, the motor means (30) beingattached to said support flange.
 11. Apparatus according to claim 1wherein the bottom pate (2) has an essentially circular outline, and thebottom surface (2a) is circular.
 12. Apparatus according to claim 1wherein the minimum predetermined height of said eccentric weight ormass (10) above the bottom plate is at least as high as the thickness ofsaid weight or mass.
 13. Apparatus according to claim 1 wherein saidbottom plate has upwardly sloping end portions (2b) extending from saidbottom surface (2a) to an upper surface thereof,the securing meansmounting said vertical support means above the upper surface of thebottom plate, and said eccentric weight or mass (10, 10a) beingpositioned within the support means by a distance above the uppersurface of at least the thickness of the weight or mass.
 14. An assemblyor group of soil compacting and tamping apparatus unitscomprising aplurality of the apparatus according to claim 1; coupling meansincluding resilient linkages (40) coupling together the support means ofthe individual apparatus units; and means (41) coupling together theshafts (5) of the apparatus units to synchronize rotary movement of theeccentric waste or masses (10) of the respective units.